Purgatory does not have any "physical" characteristics, but the Church does explain what we will experience there.
Purgatory is a mysterious state. Many people have questions about it, such as, “What does purgatory look like?”
The problem with any question about the afterlife is that only those who have experienced it can explain its attributes. Most of us have not had any near-death experiences where we can get a glimpse of what awaits us, so we rely on what God has told us through the Bible and the official teaching of the Church.
Where is Purgatory in the Bible?
Strictly speaking, purgatory is a spiritual experience, being a prelude to Heaven. Basically, after we die and before our bodies are resurrected, many of us will experience purgatory.
It is difficult to understand how we can experience something without our body, but it is a mystery we will only understand after our own death.
The Catechism of the Catholic Church explains purgatory in the following way.
All who die in God’s grace and friendship, but still imperfectly purified, are indeed assured of their eternal salvation; but after death they undergo purification, so as to achieve the holiness necessary to enter the joy of heaven. (CCC 1030)The Church gives the name Purgatory to this final purification of the elect. (CCC 1031)
Above all, purgatory is a place of purification. Saints have different depictions of it, many of them including some sort of pain. It is a type of pain that is temporary, lasting only a short time until we are able to move forward to Heaven.
C.S. Lewis (although not a Catholic) gave a profound (and comical) description of Purgatory that helps us understand why we need it. He wrote in The Great Divorce:
“Our souls demand Purgatory, don’t they? Would it not break the heart if God said to us, ‘It is true, my son, that your breath smells and your rags drip with mud and slime, but we are charitable here and no one will upbraid you with these things, nor draw away from you. Enter into joy?’ Should we not reply, ‘With submission, sir, and if there is no objection, I’d rather be cleansed first.’ ‘It may hurt, you know’—even so, sir.”
It could be described as a “washroom” before reaching the Wedding Feast of the Lamb.
However, all analogies or illustrations will never compare to what purgatory is and what it will “look” like to the “eyes” of our soul.
The good news for us is that once we reach purgatory, the only direction we can go is up!
The saints tell us what Purgatory is actually like
How long does purgatory last?